In recent years, unmanned aerial vehicle (UAV) has received people's attention and has been widely reported. Apart from the use of aerial photography, the unmanned aerial vehicle can further be used in the fields such as disaster relief, exploration, and delivery. As the price of the unmanned aerial vehicle is getting lower and lower, the quantity of users increases, and is getting more and more popular in entertainment and commercial applications. Therefore, the booming market trend of the unmanned aerial vehicle is unstoppable.
Recently, several events of unmanned aerial vehicle unexpectedly dropping off and causing harm to people are reported. Therefore, the safety problem caused by the unmanned aerial vehicle needs to be resolved as early as possible, and how to reduce the weight of vehicle body and the quantity of rotors has become a focus in the research and development of the unmanned aerial vehicle.